Hi!
This weekend, I worked on one of my bike and wanted to overhaule the hubs.
After I replaced the bearings, packed with grease, I started adjusting the cones. I found the good adjustment (as loose as possible without any play right ?) and then I proceeded on tightening the locknut.
To my great surprise, it seems that the axle moved when doing so, resulting on my adjustment to get loosened!!

I don't understand why that is happening. Do I need a vise to put my axle in so that it doesn't move ?

I hope my explanation was clear enough

Always does that.. it's trial and error.

There are two approaches. Some axles have a groove down their length and are designed so a washer with a small protrusion fits between the cone and the locknut. The protrusion sits in the groove and keeps the washer from turning and therefore the cone won't turn as you tighten the locknut (but it will still be pushed in a little so needs to be just a touch on the loose side before tightening the locknut).

Without the groove and corresponding washer you need to use a thin wrench (cone wrench) to hold the cone in position as you tighten the locknut against it.

an axle vise will keep the axle from moving .

Yes, I am using the parktool cone wrenches : one to hold the cone and another to lock the locknut

My first adjustment is never perfect. It takes a couple tries to become familiar with how much the locknut tightening process effects the adjustment. It's usually a minor amount, but it takes a little fiddling (experience) to get it just perfect.

Well, my problem is that for me, it takes forever since the axle rotates! Even if I find the perfect cone adjustment, everything gets loose because of the axle and I cannot seem to find the solution.
I found that if I overtight the cone, I can find somewhat a good adjustment since the cone will become loose as I tighten the locknut (which makes the axle moves and therefore loosen the cone). But it is all random and when it comes to hubs, I don't like randomness

But I am glad to know that it's normal.
I was wondering if I was doing something wrong or if I was using wrong tools...etc

Hmmmmm. Are you adjusting the bearing by hand? Thats what I do. Then turn the lock nut by hand until it meets the cone. Once they meet, the axle shoudn't turn as you move both wrenchs in opposite directions to one another.

Does the locknut spin feely on the axle, or are the threads a little tweaked, causing it to drag and bite the axle?

"Once they meet, the axle shoudn't turn as you move both wrenchs in opposite directions to one another." That's what I would think but for some reason the axle does move
Does the locknut spin feely on the axle, or are the threads a little tweaked, causing it to drag and bite the axle? Hmm... good call! The locknut might have bad threads to the axle might have bad threads. I will look into that!

here's what I do, tighten one side cone and lock nut with correct axle protrusion, hand tighten other cone to feels right, set a wrench on first cone and lock nut to hold it and axle from turning, tighten second lock nut too cone while holding cone with wrench, check for play/smooth repeat until feels right

Just remembered many sure smooth side of lock nut is toward cone IMHO

This.

Park AV-1, waste of time w/o one and a bench vise.

-Bandera

Try smoking after you finish repacking the hubs, makes it go quicker for me.
Tighten one side, adjust opposite cone until there is just a tiny bit of play and lock down nut, check for play, and tighten down both locknuts until there is no play. If you are really anal, check the second locknut against that cone. The end, should take about 2 minutes.

+1 on the axle vise, or something to hold the axle. I tighten the cone and lock nut on one side and then clamp that end of the axle in a small portable vise. Now the axle won't rotate when I adjust and tighten the other side. Reduces the profanity index in my shop considerably.

IME, a regular vise will clamp on to the locknut on the side you're not working on just fine for this purpose.
An axle vise can be helpful at times, but I've never needed one for this particular task.

^ +10. Bench Vise is essential for this. Turn the wheel horizontal and clamp the lower (non working) outer locknut in the jaws. Then, work from the top. You'll have access to both slotted cones (above and below), and to the top locknut. Adjust the cones to a loose position with just a "smidgen" of play, and then tighten down the top locknut while holding the top cone in place relative to the vise. The tightening will take out the play.

Trial and error until it's perfectly done. Good luck. PG

+1

If you are using quick release skewers, let me put in a plug for the Stein axle vise (scroll down; third tool up from the bottom). Designed for adjusting the hub while under pressure, so there's a lot less trial and error in getting the adjustment right.

Thanks everybody for all your insights, I appreciate everybody's advice and help.
Yesterday, I repacked my front/rear hubs but as I feared, I could NOT get the adjustment done due to the axle moving. After 30 mins, I gave up
I don't have a vise and am not able to get one (I am basically working in one of my room and I have nothing to set a vise)In this article, I found that this guy actually adjusts his cones with the wheel mounted on the bike. Do you think that this method could help holding the axle in place ?
(see bottom of the article www.cyclingnews.com news and analysis)

Yes mounting the wheel (axle) to the frame will work , I had done it many times myself when I don' have a vise near by .

I use a 3/8" nut on the right side with the QR tightened. This makes the final adjustment easier. When the QR is opened there should be a small amount of play in the axle.

Re: vises, I live in an apartment and use a vacuum vise that I picked up years ago at Home Depot (I forget the brand, but it looks something like this one). Works surprisingly well on my kitchen counter top. I've used it to cut down forks, adjust hubs, drill out brake holes, .... Just sayin'.

It just does.

I adjust the cone and locknut on one end of the axle in order to have the right amount of axle protrusion, then when I put the axle in the hub and adjust the cone on the other side, I place the first cone and locknut in a vise and it doesn't let the axle turn.